“People often say that healthier foods are more expensive, and that such costs strongly limit better diet habits,” said lead author Mayuree Rao, a junior research fellow in the Department of Epidemiology at HSPH. “But, until now, the scientific evidence for this idea has not been systematically evaluated, nor have the actual differences in cost been characterized.”

Researchers analyzed 27 studies from 10-high income countries that included price data for individual foods and for healthier and less healthy diets.

The researchers found that healthier diet patterns—for example, diets rich in fruits, vegetables, fish, and nuts—cost significantly more than unhealthy diets.

On average, a day’s worth of the most healthy diet patterns cost about $1.50 more per day than the least healthy ones.

Researchers said unhealthy diets may be cheaper because the focus is on producing a high volume of food at low costs.

Given this, researchers say more must be done to support healthy foods production at high volumes. This would in turn, reduce prices for healthy food.